The disclosure relates to current counting systems, and in particular, to current counting analog-to-digital converter for load current sensing including dynamically biased comparator.
Unless otherwise indicated herein, the approaches described in this section are not admitted to be prior art by inclusion in this section.
As part of a solution to measure load current of a low-drop out regulator (LDO), for example, a measured replica current is converted to a digital representation. This could be done with e.g. a Sigma-Delta Analog-to-Digital Converter (ADC) that is shared between all “clients”. In the particular case of load current measurement, it is desirable to filter the current measurement with a large time constant, e.g. 1 millisecond or average it over a long time period, e.g. 1 millisecond. In order to realize this large time constant, capacitors and resistors are needed of such large values that the capacitors would need to be off chip and the resistors would need a very large in chip area. This makes the RC filtering approach cost prohibitive (e.g., chip area cost, board area cost, component cost, and pin cost).